1. Field of the Invention
This invention relates to portable communication receivers having memories, regions of which may be selectively protected, and more particularly to a method and apparatus for providing user control of the remote programming of certain of the memory regions.
2. Description of the Prior Art
A number of portable communication receivers, in particular selective call receivers, or pagers, are capable of being remotely programmed, i.e. programmed by information transmitted on the receivers operating channel or frequency. Such programming has become known as over-the-air programming as compared to earlier programming methods which required the placement of the receiver in a fixture which may directly or indirectly contact the receiver in which to effect the programming. Such remotely programmable receivers provide both the user and the system operator with increased benefits which derive from their use. The user benefits by being able to request new or improved features which may now be provided without the user having to return the receiver to the system operator to make the changes. Changes, such as adding or deleting additional addresses to which the receiver is responsive, or the addition or deletion of a receiver option, can now be readily made. The system operator also benefits by being able to make these changes over-the-air at his convenience rather than at the immediate request of the user when the user arrives at the office. The system operator further benefits by being able to remotely reconfigure any or all of the receivers operating within the system in order to achieve increased message throughput and other system performance improvements when they are required, without having to recall all the receivers that are presently in operation. Such benefits, however, are offset by a number of problems heretofore not previously encountered in conventional systems where the programming is performed in the system operator's office.
One receiver having the capability of being programmed over-the-air is described in U.S. Pat. No. 4,839,628 to Davis et al., entitled "Paging Receiver having Selectively Protected Regions of Memory". The receiver utilizes protected regions of memory to prevent inadvertent modification of the memory contents, and further utilizes a password which must be transmitted together with the reconfiguration information. The password is used to protect against inadvertent modification of the memory contents in the event the receiver receives information directing such modification without the password. When the system operator controls the remote programming of the system receivers, such password protection is generally very effective. However, password protection becomes less effective when the user has the ability to call directly in to the paging terminal to request a change to the user's receiver to be made. Should a particular user's password become known, or should a group a user's passwords become known to some individuals, the possibility of mischievous or malicious sabotage of the individual's receiver or the group of receivers could occur. A method of preventing such sabotage is required.
When over-the-air programming of the receiver is executed, the reconfiguration information is first loaded into a temporary storage region of memory which is not protected, prior to reconfiguring the receiver's protected memory areas. This non-protected memory area may be a portion of the memory available in which messages are stored as they are received. When features of the receiver are to be changed by over-the-air reprogramming, generally only a small number of memory locations are required to temporarily store the reconfiguration information. However, some receiver changes, such as reconfiguring the entire operation of the receiver, may require most, if not all, of the available non-protected memory space available. When such remote programming is undertaken, all stored messages would have to be overwritten by the reconfiguration information, including messages which may have yet to have been read, in order that the change be made in the most efficient manner, with the least amount of air time utilized. Loss of such information by the user could pose a serious problem. A means is required which will provide notification to the user of any reprogramming activity which would present an impending loss of messages stored in the non-protected memory regions.